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(N Model.)

A.. W. ROSE.

Transmittialg Telephone. No. 237,131.. Patented Feb. I, 188|.

FLPERS. PHOTO-LITHOGRAPHER, WASIIDNGTON Il C.

UNITED STATES PATENT OEEICE.

ALLEN W. ROSE, OF NEW YORK, N. Y., ASSIGNOR TO CHARLES A. OHEEVER, OFSAME PLACE; SAID GHEEVER ASSIGNOR TO HIMSELF AS TRUSTEE.

TRANSMITTING-TELEPHONE.

SPECIFICATION forming part of Letters Patent No. 237,131, dated February1, 1881.

Application filed October 26, 1880. (No model.)

.To all whom it may concern:

Be it known that I, ALLEN W. ROSE, a citi- Zen of the Dominion ofCanada, now residing in the city, county, and State of New York, haveinvented certain new and useful Improvements in Transmitting-Telephones,of which the following is a specification.

My invention relates to that class of electric telephones in whichvariations of resistance of a current traversing a galvanic circuit areproduced by the varying conditions of magnetic lings capable ofinductive or magnetic action included in a magnetic field therein.

In other applications I'led simultaneously with this I have broadlyclaimed the method of operation of Athis apparatus, as well as thevarious modifications of its organization. I therefore limit my presentclaim to the specific organization specified at the close of thisspecication, the distinguishing characteristic of which is theinterposition of magnetic filings in a magnetic field between elasticdiaphragms, constituting magnetic poles.

In the accompanying drawings, Fi gurelrepresents a plan view of myimproved transmitter, with portions of the casing broken away; and Fig.2,21 vertical lou gitudinal section therethrough. A

The caseO is provided with asuitable mouthpiece, A. Magnets M Mlare'secnred in this case, arranged parallel to each other, withinterposed insulating material I between. One pole of each magnet isdrawn out, so as to constitute an elastic or yielding diaphragm, D D',parallel to each other, lying directly beneath the mouth-piece. Filingsof some metal capable of magnetic or inductive action are shown asplaced loosely in the magnetic fleld between said diaphragms. Suchfilings may be in the form of coarse powder; but I prefer to use them inthe form of slivers or lings, the length of which is three or four timesas great as that of its breadth or thickness. Filings of iron, steel,aluminum, cobalt, or nickel may be employed; but I prefer the last-namedmetal, as being less liable to oxidation from exposure to moisture.

Amixture of filings of different magnetic materials, or of filings andpowder of homogeneous or dissimilar materials, may be employed, ifpreferred.

Electro-magnets may also be used,if desired.

Each magnetis connected, by suitable wires or binding-screws, S S', to agalvanic battery, so that the circuit passes from one diaphragm to theother through the lin gs, the resistance of the circuit beingcorrelatively varied by variation in the condition of the filings,caused by impingement of sound-waves 0upon the diaphragm.

I claim as of my own invention- 1. The combination, substantially asherein set forth, of two elastic or yielding diaphragms, constitutingmagnetic poles'and included in a galvanic circuit, with metallic lingscapable of magnetic or inductive action interposed loosely in themagnetic ield between said diaphragms.

2. The combination, substantially as herein set forth, ofthe case, themouth-piece, the magnets, the interposed insulating material, thediaphragms constituting magnetic poles, the filings interposed in themagnetic field between said diaphragms in a loose condition, and agalvanic circuit, of which the lilings form a part.

In testimony whereof I have hereunto subscribed my name this 22d day ofOctober, A. D. 1880.

A. W. ROSE.

Witnesses:

E. C. DAVIDSON, WILLAED L. CANDEE,

